Minimally invasive iliosacral sentinel lymph node mapping and extirpation: A canine cadaveric study.

Objective: To develop and describe a minimally invasive surgical (MIS) approach to access, identify, and extirpate lymph nodes within the iliosacral lymph node center following sentinel lymph node mapping (SLNM).

Study design: Experimental canine cadaveric study.

Animals: Six canine cadavers.

Methods: Preoperative computed tomography (CT) with indirect CT-lymphography (CTL) was followed by MIS SLNM utilizing a near-infrared (NIR) fluorescent dye with iliosacral nodal dissection and extirpation. Each cadaver was positioned in supported sternal recumbency for all procedures. Ports were placed bilaterally in the dorsal flank. All findings and complications were recorded.

Results: All sentinel lymph nodes (SLNs) identified on CTL were identified on laparoscopic SLNM and were amenable to dissection and extirpation. In total, 37/40 iliosacral nodes identified on CT were also identified via the MIS approach. A median of 3.5 lymph nodes (range: 2-4) were extirpated per dog. No intraoperative complications occurred.

Conclusion: The MIS approach enabled identification and extirpation of lymph nodes within the iliosacral nodal center, with incorporation of SLNM of the anal sac via NIR imaging. Positioning in supported sternal recumbency with cannulas placed within the dorsal flanks allowed for effective access to all iliosacral lymph node locations.

Clinical significance: Further evaluation of SLNM via MIS in supported sternal recumbency in clinical dogs with apocrine gland anal sac adenocarcinoma is warranted in an effort to provide optimized staging information with a minimally invasive approach as compared to open surgery.